The bronchi and pulmonary blood-vessels : their anatomy and nomenclature, with a criticism of Professor Aeby's view on the bronchial tree of mammalia and of man / by William Ewart.

William Ewart

Date:: 1889

Credit: The bronchi and pulmonary blood-vessels : their anatomy and nomenclature, with a criticism of Professor Aeby's view on the bronchial tree of mammalia and of man / by William Ewart. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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$The brou- Facts and Reasons opposed to the Theory.—But the description ranuot'b™ human Lrouchial tree, which will be given in Section II., affords proof identified in that in man any distinct trace of the bronchial stem of Aeby is lost below of hmiuin the level of the upper third of the lower lobe. The same conclusion may be also derived from an inspection of the photographic reproductions of human bronchial casts contained in Professor Aeby's book. Professor His own measurements are singularly instructive on this ])oint. The third measiiro- Ventral hyparterial bronchus and the bronchial stem are found relatively to mentsiioint possess a diameter of 5'i mm. and 5'8 mm. in the right lung, and of mm. conclusion, and 64 mm. in the left lung {he. cif., p. 74), a disproportion which is admitted to be trifling. It might be suggested that it is unfair to discuss, in relation to one particular case, a theory which was devised for general application, especially since this particular case is pointed out by Aeby as affording imperfect support Opposite to the theory. On the other hand, if the whole mammalian class is to be Mammaihm ffi^en iiito Consideration in connection with the question at issue, it must series remain matter of free choice which end of the series shall be selected as the selected as ... starting- point of departure in the inquiry. Professor Aeby has preferred to start Aebyand fi'om the inferior representatives of the group, which, it is only right to own, by the r^^e the more numerous : and the conclusions which he bases upon them are author. _ ' _ . _ *■ made to apply, not without considerable strain, to the higher representatives also. I propose, with a view to testing the theory, to reverse this march. But I cannot lay claim to that even familiarity with human and with comparative anatomy which adds so much weight to any views expressed by Professor Aeby. In the field of comparative anatomy I am dealing with data, not my own, but for which I am entirely indebted to that observer. Although this circumstance detracts much from their value, the following considerations may serve a useful purpose as suggestions arising from an oi^posite standpoint, and, at any rate, they may throw seme side light upon a train of thought developed by the excluside study of the bronchial system in man. Advantages Profcssor Aeby insists mainly upon the points of agreement which he the^diffor-^ discovers in the two groups. But, by directing attention to the points of ences, difference and investigating their causes, we may step nearer to a correct ratlier than . . t, -, •■, i ■, ■, ■ i tlie simi- appreciation ot the stem-like appearance described by him ; and we may the'two^ perhaps succeed in tracing the diversities in its growth to some definite groups. anatomical and physiological influences, instead of calling to aid abstract mor])hological tendencies. Difference in the Thorax of Man and of Quadrupeds.— The contrast between the bronchial tree of man and that of most other mammals, to which attention has been called, is associated with a no less striking contrast in the shape of the thoracic cavity and in the anatomical In man a relations of the heart and of the lungs in the same animal groups. In man mun a the sternuiii is relatively long, almost reaching to the lower level of the$